A variety of excavation tools have been developed for installing underground utilities. Such excavation tools can include chain trenchers, backhoes, and vibratory plows, for example. Each of these tools has distinct advantages, and contractors often utilize more than one type of tool for a particular excavation project. Accordingly, power units or tractors have been developed to operably carry a variety of excavation tools. One such power unit is commonly referred to as a rubber tire trencher.
Referring now to FIG. 1, one example of a rubber tire trencher or tractor 10 is illustrated. The tractor 10 typically includes an engine 12 supported by a main frame 14. In the illustrated embodiment, an operator station 16 and a roll over protection bar 18 are positioned near the rear of the tractor 10. The tractor 10 further includes a front adapter 20 and a rear adapter 22 both configured to provide mounts for excavation tools or implement attachments. A front axle 24 and a rear axle 26, each with rubber tires for ground engagement, are coupled to the main frame 14 of the tractor 10.
Still referring to FIG. 1, a chain trencher 28 is one example of an excavation tool that can be attached to the tractor 10 for use in installing underground utilities. The chain trencher 28 includes a continuous digging chain 30 that is powered around a digging boom 32. The continuous digging chain 30 of the chain trencher 28 is used to form a trench in the soil by pulling material towards the surface. An auger (not shown) moves the soil cuttings to the side of the trench. Utilities are installed into the trench, and the soil cuttings are then pushed back into the trench by a backfill blade 38 (FIG. 2) to bury the installed utilities.
FIG. 1 illustrates the tractor 10 in a first exemplary configuration for installing underground utilities. The first configuration includes the chain trencher 28 mounted to the rear adapter 22 of the tractor 10. During operation, the continuous digging chain 30 rotates about the digging boom 32 in the direction shown. The operator is seated at the operator station 16, and is able to observe the chain trencher 28 while controlling the speed and direction of travel of the tractor 10.
The chain trencher 28 is shown in a lowered, operating position in FIG. 1 for formation of a trench. FIG. 2 illustrates the chain trencher 28 in a raised transport position for transportation of the chain trencher. As can be understood, the weight of the chain trencher 28 is significant. Accordingly, a weight kit 36 is often mounted at the front of the tractor 10 to counter balance of the weight of the chain trencher 28 at the rear when the trencher 28 is in the raised transport position, as shown in FIG. 2.
Referring now to FIG. 3, a backhoe 40 is another example of an excavation tool the can be used to install underground utilities. The backhoe 40 includes a bucket 42 for digging a trench in the soil. Typically, the backhoe 40 includes a separate operator station 42. In use, the operator moves the tractor 10 to the desired location. The operator then moves from the tractor operator station 16 to the backhoe operator station 42 to perform the excavation. When excavating with the backhoe 40, the tractor 10 is in a stationary position. The backhoe 40 is often used to form larger excavations so that personnel can work within the formed trench to make necessary utility connections or repairs, for example.
FIG. 3 illustrates the tractor 10 a second exemplary configuration for installing underground utilities. In particular, the second configuration includes the same set-up between the tractor 10 and chain trencher 28, as shown in FIG. 1, but now also includes the backhoe 40 mounted to the front adapter 20 of the tractor 10. In the second configuration, the backhoe 40 is mounted at the front of the tractor 10 in place of the weight kit 36. Accordingly, the backhoe 40 is used to counter balance of the weight of the chain trencher 28 at the rear when the trencher 28 is in the raised position.
Referring now to FIG. 4, a vibratory plow 44 is yet another example of an excavation tool that can be used for installing underground utilities. The illustrated plow 44 includes a vibrating blade 46. During use, the blade 46 is forced into the soil to a depth equal to the desired depth of the underground utility. As the blade 46 is pulled through the ground, a chute (not shown) follows the blade 46 and installs the utility at the desired depth.
FIG. 4 illustrates the tractor 10 in a third exemplary configuration for installing underground utilities. In the third configuration, the tractor 10 includes the same set-up between the tractor 10 and backhoe 40, as shown in FIG. 3, but now also includes the plow 44 mounted to the rear adapter 22 instead of the chain trencher 28. The plow 44 weighs less than the chain trencher 28; accordingly, the weight balance of this configuration is different than that of the others.
The weight balance of the tractor or machine 10 is different in each of the illustrated configurations. Each of the attachments (e.g., the chain trencher 28, the backhoe 40, and the plow 44) introduces a different weight stabilization relationship that requires a different balancing solution. An improved method and arrangement for properly balancing a tractor or power unit in various configurations is needed.